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Abstract:

A crystalline material represented by
M12a(M2bLc)M3dOyNx wherein
M1 is at least one element selected from alkali metals, M2 is
at least one element selected from Ca, Sr, and Ba, M3 is at least
one element selected from Si and Ge, L is at least one element selected
from rare earth elements, Bi, and Mn, a is 0.9 to 1.5, b is 0.8 to 1.2, c
is 0.005 to 0.2, d is 0.8 to 1.2, x is 0.001 to 1.0, and y is 3.0 to 4.0
or less.

Claims:

1. A crystalline material represented by
M.sup.1.sub.2a(M.sup.2.sub.bLc)M.sup.3.sub.dOyNx, wherein
M1 is at least one element selected from alkali metals, M2 is
at least one element selected from Ca, Sr, and Ba, M3 is at least
one element selected from Si and Ge, L is at least one element selected
from rare earth elements, Bi, and Mn, a is 0.9 to 1.5, b is 0.8 to 1.2, c
is 0.005 to 0.2, d is 0.8 to 1.2, x is 0.001 to 1.0, and y is 3.0 to 4.0.

2. The crystalline material according to claim 1, wherein L is at least
one element including Eu, selected from rare earth elements, Bi, and Mn.

3. The crystalline material according to claim 2, wherein L is at least
one element including divalent Eu, selected from rare earth elements, Bi,
and Mn.

4. The crystalline material according to claim 1, wherein M1 is Li,
and M3 is Si.

5. The crystalline material according to claim 1, wherein M2 is only
Sr, is Sr and Ca, or is Sr and Ba.

6. The crystalline material according to claim 1, wherein y is 4-3x/2.

7. The crystalline material according to claim 1, wherein the crystalline
material is a phosphor.

8. A light-emitting apparatus comprising a light-emitting device, and the
phosphor according to claim 7.

9. The light-emitting apparatus according to claim 8, wherein the
light-emitting device is an LED.

10. A white LED comprising an LED, and the phosphor according to claim 7.

Description:

TECHNICAL FIELD

[0001] The present invention relates to a crystalline material, and
particularly relates to a crystalline material that is a phosphor.

BACKGROUND ART

[0002] Recently, white LEDs have been used in backlights for liquid
crystal televisions and lightings, and their practical use has been
developed. The white LED market has been rapidly expanding. The white LED
is composed of a combination of an LED chip that emits the light in the
ultraviolet to blue region (wavelength is approximately 380 to 500 nm)
and a phosphor that is excited by the light emitted from the LED chip to
emit light. It is able to attain Colors of white at various color
temperatures based on the combination of the LED chip and the phosphor.

[0003] The phosphor that is excited by the light in the ultraviolet to
blue region to emit light can be suitably used for the white LED. As the
phosphor for the white LED, for example, a phosphor represented by
Li2SrSiO4:Eu is disclosed in Patent Literatures 1 and 2.

[0006] However, for example, further improvement in light emission
intensity is demanded of the phosphor such as Li2SrSiO4:Eu.

[0007] Moreover, for example, in the white LED, the phosphor is excited by
the blue light emitted from a blue LED to emit light and to obtain the
white light. However, it is known that the peak of the wavelength of the
blue light emitted from the blue LED shifts due to deterioration of the
blue LED. As the excitation spectrum of the phosphor is wider in the blue
region, it is able to suppress deviation of the color of the white LED.
Specifically, in the case where the excitation spectrum of the phosphor
for the white LED is wide, for example, from 400 to 500 nm, it is able to
suppress deviation of the color of the white LED.

[0008] An object of the present invention is to provide a crystalline
material and phosphor that exhibit high light emission intensity (high
luminance) and has a wide excitation spectrum. Also, an other object of
the present invention is to provide a light-emitting apparatus that
exhibits high luminance.

Solution to Problem

[0009] One aspect of the present invention provides a crystalline material
represented by
M12a(M2bLc)M3dOyNx. M1
is at least one element selected from alkali metals, M2 is at least
one element selected from Ca, Sr, and Ba, M3 is at least one element
selected from Si and Ge, L is at least one element selected from rare
earth elements, Bi, and Mn, a is 0.9 to 1.5 (0.9 or more and 1.5 or
less), b is 0.8 to 1.2 (0.8 or more and 1.2 or less), c is 0.005 to 0.2
(0.005 or more and 0.2 or less), d is 0.8 to 1.2 (0.8 or more and 1.2 or
less), x is 0.001 to 1.0 (0.001 or more and 1.0 or less), and y is 3.0 to
4.0 (3.0 or more and 4.0 or less). A crystalline material of the present
invention is usually a phosphor.

[0010] In the above formula, y may be 4-3x/2. Moreover, L may be at least
one element including Eu, selected from rare earth elements, Bi, and Mn
and Eu may include divalent Eu. In M1, M2, and M3, M1
may be Li, and M3 may be Si. Moreover, M2 may be only Sr, may
be Sr and Ca, or may be Sr and Ba.

[0011] Another aspect according to the present invention provides a
light-emitting apparatus comprising a light-emitting device and the
phosphor. The light-emitting device may be an LED. Further, another
aspect according to the present invention provides a white LED comprising
an LED and the phosphor.

Advantageous Effect of Invention

[0012] The crystalline material according to the present invention can
exhibit properties of a phosphor, has a wide excitation spectrum, and can
exhibit high light emission intensity. For this reason, by applying the
crystalline material to a light-emitting apparatus, it is able to attain
a light-emitting apparatus with high light emission intensity (high
luminance).

BRIEF DESCRIPTION OF DRAWINGS

[0013] FIG. 1 is a sectional view showing one embodiment of a
light-emitting apparatus.

[0015] The present embodiment relates to a crystalline material. The
crystalline material usually exhibits the properties of a phosphor, and
can be excited by the light in the blue region (peak wavelength is
approximately 380 to 500 nm) to emit light of yellow (peak wavelength is
approximately 560 to 590 nm). The crystalline material according to the
present embodiment is represented by the formula:
M12a(M2bLc)M3dOyNx. By
preparing such a composition, the crystalline material according to the
present embodiment has a wide excitation spectrum, and can attain high
light emission intensity. In the above formula, M1 represents at
least one element selected from alkali metals, M2 represents at
least one element selected from Ca, Sr, and Ba, M3 represents at
least one element selected from Si and Ge, L represents at least one
element selected from rare earth elements, Bi, and Mn, a is 0.9 to 1.5
(0.9 or more and 1.5 or less), b is 0.8 to 1.2 (0.8 or more and 1.2 or
less), c is 0.005 to 0.2 (0.005 or more and 0.2 or less), d is 0.8 to 1.2
(0.8 or more and 1.2 or less), x is 0.001 to 1.0 (0.001 or more and 1.0
or less), and y is 3.0 to 4.0 (3.0 or more and 4.0 or less).

[0016] M1 is preferably one or two or more (particularly one)
elements selected from Li, Na, and K, and more preferably Li.

[0017] M2 is preferably only Sr (Sr alone), or a combination of Sr
and other M2 element, and particularly preferably Sr alone, a
combination of Sr and Ca, or a combination of Sr and Ba. In this case,
the contents of Sr, Ca, and Ba based on the total amount of Sr, Ca, and
Ba are as follows in an atomic ratio: it is preferable that Sr be 0.5 to
1.0 (0.5≧Sr≧1.0), Ca be 0 to 0.5 (0≧Ca≧0.5),
and Ba be 0 to 0.5 (0≧Ba≧0.5); more preferably, Sr is 0.7
to 1.0 (0.7≧Sr≧1.0), Ca is 0 to 0.3
(0≧Ca≧0.3), and Ba is 0 to 0.3 (0≧Ba≧0.3);
and still more preferably, Sr is 0.95 to 1.0 (0.95≧Sr≧1.0),
Ca is 0 to 0.05 (0≧Ca≧0.05), and Ba is 0 to 0.05
(0≧Ba≧0.05).

[0018] M3 is preferably Si. When M3 is Si, it is preferable that
M1 be Li.

[0019] L is an element to be doped as a light emission ion, and it is
preferable that L contain at least Eu.

[0020] For example, L may be Eu alone, a combination of Eu and a rare
earth element other than Eu, a combination of Eu and Bi, and a
combination of Eu and Mn. Moreover, it is preferable that Eu as L
includes at least divalent Eu (Eu2+), namely, it is preferable that
Eu be only divalent Eu (Eu2+), or be a combination of divalent Eu
(Eu2+) and trivalent Eu (Eu3+). When Eu as L includes divalent
Eu (Eu2+), the crystalline material can be excited by the blue light
to emit light of yellow. In the phosphor Li2SrSiO4:Eu disclosed
in Patent Literature 1, Eu as L is only trivalent Eu (Eu3+), and the
phosphor emits light of red.

[0021] The lower limit of a is 0.9 or more, and preferably 0.95 or more.
Moreover, the upper limit of a is 1.5 or less, preferably 1.2 or less,
more preferably 1.1 or less, and particularly preferably 1.05 or less.

[0022] The lower limit of b is 0.8 or more, and preferably 0.9 or more.
Moreover, the upper limit of b is 1.2 or less, preferably 1.1 or less,
and more preferably 1.05 or less.

[0023] The lower limit of c is 0.005 or more, preferably 0.01 or more, and
more preferably 0.015 or more. Moreover, the upper limit of c is 0.2 or
less, preferably 0.1 or less, and more preferably 0.05 or less.

[0024] The lower limits of a value of b+c and d may be the same or
different, and are each preferably 0.9 or more, and more preferably 0.95
or more. The upper limits of a value of b+c and d may be the same or
different, and are each preferably 1.1 or less, and more preferably 1.05
or less. In other words, the value of b+c and d may be the same or
different, and preferably 0.9 to 1.1, more preferably 0.95 to 1.05, and
still more preferably 1.

[0025] The ratio of a to b+c (a/(b+c)), the ratio of a to d (a/d), and the
ratio of b+c to d ((b+c)/d) may be the same or different, and for
example, are each 0.9 to 1.1, and preferably 0.95 to 1.05.

[0026] The lower limit of x is 0.001 or more, and preferably 0.01 or more.
Moreover, the upper limit of x is 1.0 or less, preferably 0.5 or less,
more preferably 0.1 or less, and still more preferably 0.08 or less.

[0027] The lower limit of y is 3.0 or more, preferably 3.5 or more, and
more preferably 3.7 or more. Moreover, the upper limit of y is 4.0 or
less, preferably 3.95 or less, and more preferably 3.9 or less.

[0028] It is preferable that y be 4-3x/2. The crystalline material
according to the present embodiment and represented by the formula:
M12a(M2bLc)M3dOyNx is
generated by replacing part of oxygen by nitrogen during the production
process. For this reason, it is preferable that ideally, y=4-3x/2. In the
case where firing is performed in a reduction atmosphere, defect of anion
may be caused, and therefore y=4-3x/2 may not be satisfied.

[0029] In the composition of the crystalline material according to the
present embodiment, it is preferable that values of a, b+c, and d be
within the range of 1±0.03, and it is particularly preferable that
values of a, b+c, and d be 1. It is preferable that y be 4-3x/2, M1
be L1, M3 be Si, and M2 be Sr alone, or Sr and Ca.
Specifically, examples of the preferable composition of the crystalline
material according to the present embodiment include
Li1.96Sr0.98Eu0.02SiO3.88N0.08.

[0030] The crystal system of the crystalline material according to the
present embodiment is usually trigonal or hexagonal.

[0031] The crystalline material according to the present embodiment may
contain a halogen element (one or more elements selected from F, Cl, Br,
and I) derived from a raw material mixture described later (for example,
in the case of using a halogen compound as a raw material). The amount of
the halogen element in the crystalline material is usually the same
amount as or less than the total amount of the halogen element(s)
contained in the metal compound to be used as the raw material,
preferably 50% or less, and more preferably 25% or less based on the
total amount of the halogen element(s) contained in the metal compound to
be used as the raw material.

[0032] Moreover, the crystalline material according to the present
embodiment and other compound may be mixed to obtain a phosphor.

[0033] The crystalline material according to the present embodiment may be
produced by (i) performing at least one time of firing in a nitriding
atmosphere such as an atmosphere containing NH3 gas, and/or (ii)
using the raw material mixture containing a nitride or oxynitride in
which the nitride or oxynitride is one or more compounds (hereinafter,
these are referred to as a "nitrogen-containing compound") selected from
those containing one or more of M1, M2, M3, and L, in
firing the raw material mixture containing M1, M2, M3, and
L once or more.

[0034] Raw Material Mixture

[0035] More specifically, the raw material mixture is a mixture of a
substance containing an element M1 (first raw material), a substance
containing an element M2 (second raw material), a substance
containing an element L (third raw material), and a substance containing
an element M3 (fourth raw material). The elements M1, M2,
L, and M3 each are a metal element; for this reason, herein, the
first to fourth raw materials are referred to as a metal compound in some
cases, and the mixture thereof is referred to as a metal compound mixture
in some cases. Herein, the "metal element" is used as a meaning including
a metalloid element such as Si and Ge. The metal compound may be an oxide
of a metal M1, M2, L, or M3, or may be a substance that
decomposes or oxidizes at a high temperature (particularly firing
temperature) to form an oxide thereof. Examples of the substance that
forms an oxide include hydroxides, nitrides, halides, oxynitrides, acid
derivatives, and salts (such as carbonates, nitric acid salts, and oxalic
acid salts).

[0036] The first raw material is preferably selected from hydroxides,
oxides, carbonates, and nitrides of a metal M1 (particularly
lithium). Examples of a particularly preferable first raw material
include lithium hydroxide (LiOH), lithium oxide (Li2O), lithium
carbonate (Li2CO3), or lithium nitride (Li3N). Any of
these first raw materials may be used alone or in combinations of two or
more.

[0037] Examples of the second raw material include hydroxides, oxides,
carbonates, or nitrides of a metal M2 (particularly strontium,
barium, and calcium, for example). More specifically, the second raw
material is selected from strontium hydroxide (Sr(OH)2), strontium
oxide (SrO), strontium carbonate (SrCO3), strontium nitride
(Sr3N2), and calcium carbonate (CaCO3). Any of these
second raw materials may be used alone or in combinations of two or more.

[0038] It is preferable that the third raw material be a hydroxide, an
oxide, a carbonate, a chloride, or a nitride of a metal L (particularly
europium). The third raw material is selected from, for example, europium
hydroxide (Eu(OH)2, Eu(OH)3), europium oxide (EuO,
Eu2O3), europium carbonate (EuCO3,
Eu2(CO3)3), europium chloride (EuCl2, EuCl3),
europium nitrate (Eu(NO3)2, Eu(NO3)3), and europium
nitride (Eu3N2, EuN). Any of these third raw materials may be
used alone or in combinations of two or more.

[0040] Mixing of the first raw material to the fourth raw material may be
performed by one of a wet method and a dry method. In the mixing, an
ordinary apparatus may be used. Examples of such an apparatus include a
ball mill, a V type mixer, and a stirrer.

[0041] Firing

[0042] The firing condition may be properly changed as long as the firing
condition is a condition that allows the crystalline material to be
obtained. The number of times of firing may be one or two or more, and
preferably two or more. The firing atmosphere may be an inert gas
atmosphere (such as nitrogen and argon), an oxidizing gas atmosphere
(such as air, oxygen, and a mixed gas of oxygen and an inert gas), or a
reducing gas atmosphere (such as a mixed gas of 0.1 to 10% by volume of
hydrogen and an inert gas, NH3 gas, and a mixed gas of 10 to less
than 100% by volume of NH3 gas and an inert gas), for example. The
firing atmosphere may be pressurized, when necessary. The atmosphere can
also be changed for each firing. However, it is preferable that at least
one firing be performed in the nitriding atmosphere.

[0043] More preferably, the first firing is performed in a non-nitriding
atmosphere, and the second or later firing is performed in a nitriding
atmosphere. The non-nitriding atmosphere is, for example, an atmosphere
that does not containin NH3 gas, or an atmosphere that does not
contain high pressure (approximately 0.1 to 5.0 MPa) N2.

[0044] In the case where the raw material mixture does not contain
nitrogen-containing compound, by doing as above, silicate or germanate
represented by M12a(M2bLc)M3dOw
can be formed by the first firing. By performing the second or later
firing in a nitriding atmosphere, nitrogen can be introduced into the
silicate or germanate represented by
M12a(M2bLc)M3dOw to from a
crystalline material represented by
M12a(M2bLc)M3dOyNx.

[0045] In the case where the raw material mixture contains a
nitrogen-containing compound, by doing as above, a compound represented
by M12a(M2bLc)M3dOwNz can be
formed by the first firing. By performing the second or later firing in a
nitriding atmosphere, nitrogen can be introduced such that the compound
represented by the
M12a(M2bLc)M3dOwNz becomes a
composition represented by
M12a(M2bLc)M3dOyNx. In the
compositional formula above, y<w, and x>z. Moreover, it is
preferable that w=4-3/2×z. Similarly to the relationship between x
and y described above, w=4-3/2×z may not be satisfied, however.

[0046] In the case where the raw material mixture contains the
nitrogen-containing compound, however, the firing in the nitriding
atmosphere may not always be performed, and only the firing in the
non-nitriding atmosphere may be performed. In this case, by adjusting the
amount of the nitrogen-containing compound in the raw material mixture,
the amount of nitrogen in the crystalline material represented by
M12a(M2bLc)M3dOyNx may be
controlled.

[0047] Examples of the gas for providing the nitriding atmosphere include
NH3 gas (100% by volume), a mixed gas of not less than 10% by volume
and less than 100% by volume of NH3 gas and an inert gas, and high
pressure (approximately 0.1 to 5.0 MPa) nitrogen gas. The gas for
providing the nitriding atmosphere is preferably NH3 gas (100% by
volume) or a mixed gas of not less than 50% by volume and less than 100%
by volume of NH3 gas and an inert gas.

[0048] The firing temperature is usually 700 to 1000° C.,
preferably 750 to 950° C., and more preferably 800 to 900°
C. The firing time is usually 1 to 100 hours, preferably 10 to 90 hours,
and more preferably 20 to 80 hours.

[0049] In the case where the raw material mixture is fired in a strong
reducing atmosphere, a proper amount of carbon may be added to the metal
compound, and firing may be performed. Moreover, in the case where the
raw material mixture is fired in an inert atmosphere or in an oxidizing
atmosphere, it is preferable that firing be subsequently performed in a
reducing atmosphere.

[0050] In the case where a hydroxide, a carbonate, a nitric acid salt, a
halide, or an oxalic acid salt is used as the metal compound, the method
for producing a crystalline material according to the present embodiment
may further comprise a step of calcining these metal compounds before
firing the raw material mixture or before mixing the metal compounds. By
keeping the metal compound at 500 to 800° C. for approximately 1
to 100 hours (preferably 10 to 90 hours), for example, the metal compound
may be calcined.

[0051] In the calcination or firing, a reaction accelerator can be added
to the metal compound or a mixture of these. Namely, the calcination or
firing may be performed in the presence of the reaction accelerator. By
adding the reaction accelerator, the light emission intensity of the
crystalline material can be increased. The reaction accelerator is
selected from, for example, alkali metal halides, alkali metal
carbonates, alkali metal hydrogencarbonates, halogenated ammonium, oxide
of boron (B2O3), and oxo acid of boron (H3BO3). The
alkali metal halide is preferably fluorides of alkali metals or chlorides
of alkali metals, and LiF, NaF, KF, LiCl, NaCl, or KCl, for example. The
alkali metal carbonates are Li2CO3, Na2CO3, or
K2CO3, for example. The alkali metal hydrogencarbonate is
NaHCO3, for example. The ammonium halide is NH4Cl or NH4I,
for example.

[0052] The calcined product or the fired products after the respective
firings may be subjected to one or more treatments such as crushing,
mixing, washing, and classification, when necessary. A ball mill, a V
type mixer, a stirrer, and a jet mill can be used in crushing and mixing,
for example.

[0053] In order to obtain the crystalline material
M12a(M2bLc)M3dOyNx, the
mixing proportion of the metal compound may be adjusted such that the
ratio (M1 element):(M2 element):(L element):(M3 element)
is 2a:b:c:d, and the firing time under a nitriding atmosphere may be
adjusted. Moreover, in the case where the raw material mixture contains
the nitrogen-containing compound, by adjusting the amount of these to be
used and the firing condition (such as firing time) under the nitriding
atmosphere, the content of nitrogen in the crystalline material (value of
x) may be adjusted. Moreover, the content of oxygen in the crystalline
material (value of y) can be controlled by adjusting the firing condition
under an O2 containing atmosphere (such as O2 concentration in
the firing atmosphere, and the firing time under the O2 containing
atmosphere).

[0054] A crystalline material according to the present embodiment can
exhibit properties of a phosphor. The crystalline material has a wide
excitation spectrum suitable for the white LED. The crystalline material
can exhibit the light emission intensity higher than that of
Li2SrSiO4:Eu by exciting the crystalline material by the blue
light. In the crystalline material according to the present embodiment,
the ratio of the light emission intensity (2) at excitation by the light
with a wavelength of 500 nm to the light emission intensity (1) at
excitation by the light with a wavelength of 450 nm (light emission
intensity (2)/light emission intensity (1)) is 80% or more, preferably
85% or more, and more preferably 90% or more. Accordingly, the
crystalline material according to the present embodiment can be suitably
used in the light-emitting apparatus (such as the white LED). The
light-emitting apparatus according to the present embodiment includes a
light-emitting device (exciting source) and a phosphor. The white LED
according to the present embodiment comprises an LED and a phosphor. The
phosphor is the crystalline material according to the present embodiment.
It is preferable that the light-emitting device be an LED.

[0055] The white LED will be described in more detail. The white LED is
usually composed of a light-emitting device (LED chip) that emits the
ultraviolet to blue light (wavelength is approximately 200 to 500 nm, and
preferably approximately 380 to 500 nm) and a fluorescent layer including
a phosphor. The white LED can be produced, for example, by the methods
disclosed in Japanese Patent Application Laid-Open Nos. 11-31845 and
2002-226846. Namely, for example, the white LED can be produced by the
method in which the light-emitting device is sealed with a
light-transmittable resin such as an epoxy resin and a silicone resin,
and the surface thereof is covered with the phosphor. If the amount of
the phosphor is properly set, the white LED is formed to emit the light
of a desired white color.

[0056] FIG. 1 is a sectional view showing one embodiment of the
light-emitting apparatus. A light-emitting apparatus 1 shown in FIG. 1
includes a light-emitting device 10, and a fluorescent layer 20 provided
on the light-emitting device 10. The phosphor that forms the fluorescent
layer 20 receives the light from the light-emitting device 10 to be
excited and emit fluorescence. By properly setting the kind, amount, and
the like of the phosphor that forms the fluorescent layer 20, white light
emission can be obtained. Namely, a white LED can be formed. The
light-emitting apparatus or white LED according to the present embodiment
is not limited to the form shown in FIG. 1, and can be properly modified
without departing from the gist of the present invention.

[0057] As the phosphor, the crystalline material according to the present
embodiment may be contained alone, or other phosphor may be further
contained. The other phosphor is selected from, for example,
BaMgAl10O17:Eu, (Ba,Sr, Ca)(Al,Ga)2S4:Eu,
BaMgAl10O17:(Eu,Mn), BaAl12O19:(Eu,Mn), (Ba,Sr,
Ca)S:(Eu,Mn), YBO3:(Ce,Tb), Y2O3:Eu, Y2O2S:Eu,
YVO4:Eu, (Ca,Sr)S:Eu, SrY2O4:Eu, Ca--Al--Si--O--N:Eu,
(Ba,Sr, Ca)Si2O2N2:Eu, β-sialon,
CaSc2O4:Ce, and Li--(Ca,Mg)-Ln-Al--O--N:Eu (wherein Ln
represents a rare earth element other than Eu).

[0058] Examples of the light-emitting device that emits light with a
wavelength of 200 nm to 500 nm include ultraviolet LED chips blue LED
chips and the like. In these LED chips, a semiconductor having a layer of
GaN, (0<i<1), IniAljGa1-i-jN (0<i<1,
0<j<1, i+j<1) is used as the light emitting layer. By changing
the composition of the light emitting layer, the light emission
wavelength can be changed.

[0059] The crystalline material according to the present embodiment can
also be used in the light-emitting apparatus other than the white LED,
for example, light-emitting apparatuses whose phosphor exciting source is
vacuum ultraviolet light (such as PDP); light-emitting apparatuses whose
phosphor exciting source is ultraviolet light (such as backlights for
liquid crystal displays and three band fluorescent lamps); and
light-emitting apparatuses whose phosphor exciting source is an electron
beam (such as CRT and FED).

EXAMPLES

[0060] Hereinafter, the present invention will be more specifically
described using Examples. The present invention will not be limited by
Examples below. The present invention, of course, can be implemented by
an aspect to which proper modifications are added within the range in
which the modifications can be complied with the gist described above and
that described later, and those modifications are included in the
technical scope of the present invention.

[0061] The light emission intensity of the crystalline material obtained
in Examples below was determined using a fluorescence spectrometer (made
by JASCO Corporation, FP-6500). For X-ray diffraction (XRD) measurement
of the crystalline material, an X-ray diffractometer (made by Rigaku
Corporation, RINT2000) was used. The valency proportion of Eu in the
crystalline material was evaluated by X-ray absorption fine structure
(XAFS) measurement.

[0062] XAFS measurement was performed in the SPring-8 using a beam line
BL14B2 according to a transmission method. The Eu-L3 absorption edge of
6650 to 7600 eV was the measurement region. As the standard sample of
Eu2+ (6972 eV), BaMgAl10O17:Eu2+ (BAM) was used. As
the standard sample of Eu3+ (6980 eV), europium oxide (made by
Shin-Etsu Chemical Co., Ltd., purity of 99.99%) was used. The X-ray
absorption near edge structure (XANES) spectrum was obtained using an
analyzing program (made by Rigaku Corporation, REX2000) by processing the
XAFS data of the samples based on the background. Subsequently, using the
XANES spectra of the Eu2+ standard sample and the Eu3+ standard
sample, pattern fitting of the XANES spectra of the samples were
performed, and the proportion of Eu2+ in the sample was calculated
from the proportion of Eu2+ peaks.

[0063] The contents of oxygen and nitrogen in the crystalline material
were measured using an EMGA-920 made by HORIBA, Ltd. For the content of
oxygen, a non-dispersive infrared absorption method was used. For the
content of nitrogen, a thermal conductivity method was used.

Example 1

[0064] Lithium carbonate (made by KANTO CHEMICAL CO., INC., purity of
99%), strontium carbonate (made by Sakai Chemical Industry Co., Ltd.,
purity of 99% or more), europium oxide (made by Shin-Etsu Chemical Co.,
Ltd., purity of 99.99%), and silicon dioxide (made by Nippon Aerosil Co.,
Ltd.: purity of 99.99%) were weighed such that the atomic ratio of
Li:Sr:Eu:Si was 1.96:0.98:0.02:1.0, and these were mixed with a dry ball
mill for 6 hours to obtain a metal compound mixture.

[0065] The mixture was fired in the air at 750° C. for 10 hours,
and then gradually cooled to room temperature. The obtained fired product
was crushed, and fired under the NH3 gas atmosphere at 800°
C. for 3 hours to obtain a crystalline compound (crystalline material)
represented by the formula
Li1.96Sr0.98Eu0.02SiO3.99N0.005.

Example 2

[0066] Lithium carbonate (made by KANTO CHEMICAL CO., INC., purity of
99%), strontium carbonate (made by Sakai Chemical Industry Co., Ltd.,
purity of 99% or more), europium oxide (made by Shin-Etsu Chemical Co.,
Ltd., purity of 99.99%), and silicon dioxide (made by Nippon Aerosil Co.,
Ltd.: purity of 99.99%) were weighed such that the atomic ratio of
Li:Sr:Eu:Si was 1.96:0.98:0.02:1.0, and these were mixed with a dry ball
mill for 6 hours to obtain a metal compound mixture.

[0067] The mixture was fired in the air at 750° C. for 10 hours,
and then gradually cooled to room temperature. The obtained fired product
was crushed, and fired under the NH3 gas atmosphere at 800°
C. for 6 hours to obtain a crystalline compound (crystalline material)
represented by the formula
Li1.96Sr0.98Eu0.02SiO3.98N0.010.

Example 3

[0068] Lithium carbonate (made by KANTO CHEMICAL CO., INC., purity of
99%), strontium carbonate (made by Sakai Chemical Industry Co., Ltd.,
purity of 99% or more), europium oxide (made by Shin-Etsu Chemical Co.,
Ltd., purity of 99.99%), and silicon dioxide (made by Nippon Aerosil Co.,
Ltd.: purity of 99.99%) were weighed such that the atomic ratio of
Li:Sr:Eu:Si was 1.96:0.98:0.02:1.0, and these were mixed with a dry ball
mill for 6 hours to obtain a metal compound mixture.

[0069] The mixture was fired in the air at 750° C. for 10 hours,
and then gradually cooled to room temperature. The obtained fired product
was crushed, and fired under the NH3 gas atmosphere at 800°
C. for 12 hours to obtain a crystalline compound (crystalline material)
represented by the formula
Li1.96Sr0.98EU0.02SiO3.92N0.053.

Example 4

[0070] Lithium carbonate (made by KANTO CHEMICAL CO., INC., purity of
99%), strontium carbonate (made by Sakai Chemical Industry Co., Ltd.,
purity of 99% or more), europium oxide (made by Shin-Etsu Chemical Co.,
Ltd., purity of 99.99%), and silicon dioxide (made by Nippon Aerosil Co.,
Ltd.: purity of 99.99%) were weighed such that the atomic ratio of
Li:Sr:Eu:Si was 1.96:0.98:0.02:1.0, and these were mixed with a dry ball
mill for 6 hours to obtain a metal compound mixture.

[0071] The mixture was fired in the air at 750° C. for 10 hours,
and then gradually cooled to room temperature. The obtained fired product
was crushed, and fired under the NH3 gas atmosphere at 800°
C. for 24 hours to obtain a crystalline compound (crystalline material)
represented by the formula
Li1.96Sr0.98Eu0.02SiO3.88N0.082.

Example 5

[0072] Lithium carbonate (made by KANTO CHEMICAL CO., INC., purity of
99%), strontium carbonate (made by Sakai Chemical Industry Co., Ltd.,
purity of 99% or more), europium oxide (made by Shin-Etsu Chemical Co.,
Ltd., purity of 99.99%), and silicon dioxide (made by Nippon Aerosil Co.,
Ltd.: purity of 99.99%) were weighed such that the atomic ratio of
Li:Sr:Eu:Si was 1.96:0.98:0.02:1.0, and these were mixed with a dry ball
mill for 6 hours to obtain a metal compound mixture.

[0073] The mixture was fired under the NH3 gas atmosphere at
800° C. for 12 hours to obtain a crystalline compound (crystalline
material) represented by the formula
Li1.96Sr0.98Eu0.02SiO3.97N0.022.

[0075] The mixture was fired in the air at 750° C. for 10 hours,
and then gradually cooled to room temperature. The obtained fired product
was crushed, and fired under the NH3 gas atmosphere at 800°
C. for 12 hours to obtain a crystalline compound (crystalline material)
represented by the formula
Li1.96Sr0.97Ca0.01Eu0.02SiO3.93N0.046.

[0077] The mixture was fired in the air at 750° C. for 10 hours,
and then gradually cooled to room temperature. The obtained fired product
was crushed, and fired under the NH3 gas atmosphere at 800°
C. for 12 hours to obtain a crystalline compound (crystalline material)
represented by the formula
Li1.96Sr0.97Ba0.01Eu0.02SiO3.94N0.040.

[0078] Crystalline materials in Examples 8 to 10 were obtained in the same
manner as in Example 3 except that the proportions (atomic ratios) of Eu
and Sr in the raw material were changed such that the compositional
formula shown in Table 1 was attained.

[0079] Crystalline materials in Examples 11 to 13 were obtained in the
same manner as in Example 3 except that the proportion (atomic ratio) of
Li in the raw material was changed such that the compositional formula
shown in Table 1 was attained.

[0080] Crystalline materials in Examples 14 to 16 were obtained in the
same manner as in Example 6 except that the proportions (atomic ratios)
of Ca and Sr in the raw material were changed such that the compositional
formula shown in Table 1 was attained.

[0081] Crystalline materials in Examples 17 to 19 were obtained in the
same manner as in Example 7 except that the proportions (atomic ratios)
of Ba and Sr in the raw material were changed such that the compositional
formula shown in Table 1 was attained.

[0082] In Examples 8 to 19, the proportions (atomic ratios) of the M1
element, the M2 element, the L element, and the M3 element in
the raw material are the same atomic ratio of these elements in the
compositional formula shown in Table 1.

Comparative Example 1

[0083] Lithium carbonate (made by KANTO CHEMICAL CO., INC., purity of
99%), strontium carbonate (made by Sakai Chemical Industry Co., Ltd.,
purity of 99% or more), europium oxide (made by Shin-Etsu Chemical Co.,
Ltd., purity of 99.99%), and silicon dioxide (made by Nippon Aerosil Co.,
Ltd.: purity of 99.99%) were weighed such that the atomic ratio of
Li:Sr:Eu:Si was 1.96:0.98:0.02:1.0, and these were mixed with a dry ball
mill for 6 hours to obtain a metal compound mixture.

[0084] The mixture was fired under the mixed gas atmosphere of N2 and
5% by volume of H2 at 800° C. for 24 hours, and then
gradually cooled to room temperature to obtain a crystalline compound
represented by the formula
Li1.96(Sr0.98Eu0.02)SiO4.00.

Comparative Example 2

[0085] Lithium carbonate (made by KANTO CHEMICAL CO., INC., purity of
99%), strontium carbonate (made by Sakai Chemical Industry Co., Ltd.,
purity of 99% or more), europium oxide (made by Shin-Etsu Chemical Co.,
Ltd., purity of 99.99%), and silicon dioxide (made by Nippon Aerosil Co.,
Ltd.: purity of 99.99%) were weighed such that the atomic ratio of
Li:Sr:Eu:Si was 1.96:0.98:0.02:1.0, and these were mixed with a dry ball
mill for 6 hours to obtain a metal compound mixture.

[0086] The mixture was fired under the mixed gas atmosphere of N2 and
5% by volume of H2 at 800° C. for 24 hours, and then
gradually cooled to room temperature. The obtained fired product was
crushed, and fired under the mixed gas atmosphere of N2 and 5% by
volume of H2 at 800° C. for 24 hours to obtain a crystalline
compound represented by the formula
Li1.96(Sr0.98Eu0.02)SiO4.00.

Comparative Example 3

[0087] Lithium carbonate (made by KANTO CHEMICAL CO., INC., purity of
99%), strontium carbonate (made by Sakai Chemical Industry Co., Ltd.,
purity of 99% or more), europium oxide (made by Shin-Etsu Chemical Co.,
Ltd., purity of 99.99%), and silicon dioxide (made by Nippon Aerosil Co.,
Ltd.: purity of 99.99%) were weighed such that the atomic ratio of
Li:Sr:Eu:Si was 1.96:0.98:0.02:1.0, and these were mixed with a dry ball
mill for 6 hours to obtain a metal compound mixture.

[0088] The mixture was fired in the air at 750° C. for 10 hours,
and then gradually cooled to room temperature. The obtained fired product
was crushed, and fired under the mixed gas atmosphere of N2 and 5%
by volume of H2 at 800° C. for 24 hours to obtain a
crystalline compound represented by the formula
Li1.96(Sr0.98Eu0.02)SiO4.00.

Comparative Example 4

[0089] Lithium carbonate (made by KANTO CHEMICAL CO., INC., purity of
99%), strontium carbonate (made by Sakai Chemical Industry Co., Ltd.,
purity of 99% or more), europium oxide (made by Shin-Etsu Chemical Co.,
Ltd., purity of 99.99%), and silicon dioxide (made by Nippon Aerosil Co.,
Ltd.: purity of 99.99%) were weighed such that the atomic ratio of
Li:Sr:Eu:Si was 2.00:0.98:0.02:1.0, and these were mixed with a dry ball
mill for 6 hours to obtain a metal compound mixture.

[0090] The mixture was fired in the air at 750° C. for 10 hours,
and then gradually cooled to room temperature. The obtained fired product
was crushed, and fired under the mixed gas atmosphere of N2 and 5%
by volume of H2 at 800° C. for 24 hours to obtain a compound
represented by the formula
Li2.00(Sr0.98Eu0.02)SiO4.00.

[0091] The properties of the crystalline materials obtained in Examples 1
to 19 and Comparative Examples 1 to 4 are shown in Table 1. The light
emission intensity (1) designates the peak intensity of the light
emission spectrum when the crystalline material is excited by the light
with a wavelength of 450 nm, and the light emission intensity (2)
designates the peak intensity of the light emission spectrum when the
crystalline material is excited by the light with the wavelength of 500
nm. The light emission intensities (1) and (2) each are expressed as a
relative value when the light emission intensity (1) in Comparative
Example 1 is 100. Moreover, the light emission spectrum in Example 4 and
that in Comparative Example 1 are shown in FIG. 2.

[0092] From Table 1, in the crystalline materials obtained in Examples 1
to 19, both of the light emission intensities (1) and (2) are higher than
those of the crystalline materials obtained in Comparative Examples 1 to
4. Moreover, in the crystalline materials obtained in Comparative
Examples 1 to 4, the light emission intensity (2) reduced to less than
75% of the light emission intensity (1), while in the crystalline
materials obtained in Examples 1 to 19, the light emission intensity (2)
was equal to the light emission intensity (1), or if reduced, was 75% or
more (preferably 80% or more). Namely, it turned out that in the
crystalline materials obtained in Examples 1 to 19, reduction in the
light emission intensity can be suppressed even if the excitation
wavelength is deviated.

INDUSTRIAL APPLICABILITY

[0093] The crystalline material according to the present invention can
exhibit the properties of the phosphor, has a wide excitation spectrum in
the blue region, and exhibits high light emission intensity by excitation
by the blue light; accordingly, the crystalline material is suitably used
in the phosphor unit for the light-emitting apparatus represented by the
white LED.